Electric switches



March 25, 1958 G. A. GAYLER 2,828,371

ELECTRIC SWITCHES Filed May 1s, 1955 l V i R51. 25 2l K n a imi x x 14 ATTORNEY United States Patent O f ELECTRIC SWITCHES George Alfred Gayler, Bletchley, England, assignor to Wipac Development Limited, Bletchley, England Application May 16, 1955, Serial No. 508,680

Claims priority, application Great Britain June 3, 1954 Claims. (Cl. 200-16) The present invention relates to electric switches of the three-pole one-way type, that is to say of the type having three terminals which in the o position are insulated from one another and in the on position are all con nected together. Such switches may be required, for example, as will be explained later, as stop switches operated by the brake pedal of a road vehicle to illuminate two spaced stop lights when it is required that the stop lights should also be used as turn indicating lights.

According to the present invention a three-pole, oneway electric switch comprises two members which are movable relatively to one another in a first direction when the switch is changed from its on to its ofi position and vice versa, one of the members carrying three mutually-insulated yielding contacts and the other member carrying a contact piece mounted in such a manner as to be capable of limited movements relatively to the said other member in a plane at right angles to the said first direction, the arrangement being such that when the switch is adjusted to its on position the contact piece is free to slide in the said plane to take up a position of equilibrium in contact with the three yielding contacts thereby enabling very good electric contact to be obtained between the contact piece and the three yielding contacts. The contact piece may be constrained against rotary movement in the said plane: for example it may be provided with three flats adapted to engage the three yielding contacts, respectively, in the on position and suitable shaped portions on the first-named member in the off position.

In a preferred construction the contact piece has an approximately hexagonal outer contour and is in the form of a fiat annulus mounted between two insulating members which act as guides for the contact piece and permit movement thereof in the said plane.

The invention will be described, by way of example, with reference to the drawings accompanying the specification in which Fig. 1 is a view in longitudinal section of a stop switch according to the invention,

Fig. 2 is a view in end elevation from the right in Fig. l with the cover and sealing washer removed,

Fig. 3 is a view in end elevation from the left in Fig. l, and

Fig. 4 is a circuit diagram showing how the switch of Figs. l to 3 may be used as a stop switch operated by a brake pedal.

Referring to Figs. l to 3, the fixed member of the switch. comprises a mounting plate carrying a hollow insulating body portion 11. Within a hexagonal space in the body 11 are three yielding contacts 12 connected to three terminal pieces 13, respectively, as shown in the case of one terminal piece in Fig. l. The movable member comprises a rod 14 having a head 15. A contact piece 16 lil 2,828,371 Patented Mar. 25, 1958 having a hexagonal outer contour is mounted between two insulating washers 17 and 18 and the parts 16, 17 and y18 are pressed by a spring 19 against the head 15 acting as an abutment. The spring 19 bears against a washer 20 which abuts against a sealing washer 21, for example of felt, on the inside of a cover 22 which is secured on the insulating body portion 11 by three tongues 23 cut out of the cover and engaging in suitable notches formed in the body portion 11.

Connections are made with the terminal pieces 13 by screws 24 and the terminal pieces are provided with insulating covers 25.

The rod 14 may be coupled to the brake pedal through a spring 26. The rod 14 is free to rotate relatively to the contact piece 16 and body portion 11.

In Fig. 4 the switch of Figs. 1 to 3 is shown at 27. It is arranged, when in the on position, to close a circuit between a battery 28 and two spaced red lamps 29 on a motor cycle or motor car. When a turn indicator switch 30 is set to the right or left, a circuit is closed from the battery 28 and the appropriate one of the lamps 29 through a thermo cut-out switch 31, of well-known type, whereby the lamp that is operative is caused to liash.

I claim:

l. A three-pole one-way electric switch comprising two members which are movable relatively to one another in a first direction when the switch is changed from its on to its oit position and vice versa, three mutually-insulated yielding contacts mounted on one of said members, a contact piece capable of substantial but limited movements at right angles to said first direction to assure good electric contact between said three mutually-insulated yielding contacts and said contact piece, and guide means having two guide surfaces facing one another and in planes substantially at right angles to said first direction, said surfaces being in guiding engagement with said contact piece.

2. An electric switch according to claim l, comprising means constraining said contact piece against rotary movement about said first direction.

3. An electric switch according to claim l, wherein said contact piece is provided with three flats positioned to engage the three yielding contacts, respectively, in the on" position and to engage suitably shaped portions on the iirst-narned member in the off position.

4. A three-pole one-way electric switch comprising two members which are movable relative to one another in a first direction when said switch is changed from on to off position and in an opposite direction when said switch is changed from o to on position, three mutually-insulated yielding contacts mounted on one of said members, a contact piece capable of substantial but limited movements at right angles to said first direction to assure good electrical contact between said three mutuallyinsulated yielding contacts and said contact piece, and guide means consisting of two insulating members having guide surfaces facing one another and in planes substantially at right angles to said first direction, said surfaces being in guiding engagement with said contact piece, said contact piece having an approximately hexagonal outer contour and being in the form of a fiat annulus mounted between said two insulating members which act as guides for said contact piece and permit movement thereof in said planes. v

5. A three-pole one-way switch comprising a hollow body portion, three yielding contacts mounted in the interior of said body portion, extending in a first direction,

References Cited in the file of this patent UNITED STATES PATENTS Heeney Feb. 1, 1916 Richards Dec. 23, 1919 La Londe Feb. 14, 1922 Harley Aug. 10, 1926 Raley et al Mar. 29, 1927 Thomas Dec. 23, 1930 Allen Oct. 3, 1933 

